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<H1 class="no-header">curs_termcap 3x</H1>
<PRE>
<STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>                                              <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>




</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       <STRONG>PC</STRONG>, <STRONG>UP</STRONG>, <STRONG>BC</STRONG>, <STRONG>ospeed</STRONG>, <STRONG>tgetent</STRONG>, <STRONG>tgetflag</STRONG>, <STRONG>tgetnum</STRONG>, <STRONG>tgetstr</STRONG>, <STRONG>tgoto</STRONG>, <STRONG>tputs</STRONG> -
       <STRONG>curses</STRONG> emulation of termcap


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
       <STRONG>#include</STRONG> <STRONG>&lt;term.h&gt;</STRONG>

       <STRONG>extern</STRONG> <STRONG>char</STRONG> <STRONG>PC;</STRONG>
       <STRONG>extern</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG> <STRONG>UP;</STRONG>
       <STRONG>extern</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG> <STRONG>BC;</STRONG>
       <STRONG>extern</STRONG> <STRONG>short</STRONG> <STRONG>ospeed;</STRONG>

       <STRONG>int</STRONG> <STRONG>tgetent(char</STRONG> <STRONG>*</STRONG><EM>bp</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>name</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>tgetflag(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>id</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>tgetnum(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>id</EM><STRONG>);</STRONG>
       <STRONG>char</STRONG> <STRONG>*tgetstr(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>id</EM><STRONG>,</STRONG> <STRONG>char</STRONG> <STRONG>**</STRONG><EM>area</EM><STRONG>);</STRONG>
       <STRONG>char</STRONG> <STRONG>*tgoto(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>cap</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>col</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>row</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>tputs(const</STRONG> <STRONG>char</STRONG> <STRONG>*</STRONG><EM>str</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>affcnt</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <STRONG>(*</STRONG><EM>putc</EM><STRONG>)(int));</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
       These routines are included as a conversion aid for programs  that  use
       the  <EM>termcap</EM>  library.  Their parameters are the same, but the routines
       are emulated using the <EM>terminfo</EM> database.  Thus, they can only be  used
       to  query  the  capabilities  of entries for which a terminfo entry has
       been compiled.


</PRE><H3><a name="h3-Initialization">Initialization</a></H3><PRE>
       The <STRONG>tgetent</STRONG> routine loads the entry for <EM>name</EM>.  It returns:

          1  on success,

          0  if there is no such entry (or that it is a generic  type,  having
             too little information for curses applications to run), and

          -1 if the terminfo database could not be found.

       This differs from the <EM>termcap</EM> library in two ways:

          <STRONG>o</STRONG>   The  emulation  ignores  the buffer pointer <EM>bp</EM>.  The <EM>termcap</EM> li-
              brary would store a copy of the terminal description in the area
              referenced  by this pointer.  However, ncurses stores its termi-
              nal descriptions in compiled binary form, which is not the  same
              thing.

          <STRONG>o</STRONG>   There is a difference in return codes.  The <EM>termcap</EM> library does
              not check if the terminal description is marked with the <EM>generic</EM>
              capability,  or  if the terminal description has cursor-address-
              ing.


</PRE><H3><a name="h3-Capability-Values">Capability Values</a></H3><PRE>
       The <STRONG>tgetflag</STRONG> routine gets the boolean entry for <EM>id</EM>, or zero  if  it  is
       not available.

       The  <STRONG>tgetnum</STRONG>  routine gets the numeric entry for <EM>id</EM>, or -1 if it is not
       available.

       The <STRONG>tgetstr</STRONG> routine returns the string entry for <EM>id</EM>, or zero if  it  is
       not  available.  Use <STRONG>tputs</STRONG> to output the returned string.  The <EM>area</EM> pa-
       rameter is used as follows:

          <STRONG>o</STRONG>   It is assumed to be the address of a pointer to a buffer managed
              by the calling application.

          <STRONG>o</STRONG>   However, ncurses checks to ensure that <STRONG>area</STRONG> is not NULL, and al-
              so that the resulting buffer pointer is  not  NULL.   If  either
              check fails, the <EM>area</EM> parameter is ignored.

          <STRONG>o</STRONG>   If  the  checks succeed, ncurses also copies the return value to
              the buffer pointed to by <EM>area</EM>, and the <EM>area</EM> value will be updat-
              ed to point past the null ending this value.

          <STRONG>o</STRONG>   The  return  value itself is an address in the terminal descrip-
              tion which is loaded into memory.

       Only the first two characters of the <STRONG>id</STRONG> parameter of <STRONG>tgetflag</STRONG>,  <STRONG>tgetnum</STRONG>
       and <STRONG>tgetstr</STRONG> are compared in lookups.


</PRE><H3><a name="h3-Formatting-Capabilities">Formatting Capabilities</a></H3><PRE>
       The <STRONG>tgoto</STRONG> routine expands the given capability using the parameters.

       <STRONG>o</STRONG>   Because  the  capability may have padding characters, the output of
           <STRONG>tgoto</STRONG> should be passed to <STRONG>tputs</STRONG> rather than some other output func-
           tion such as <STRONG>printf(3)</STRONG>.

       <STRONG>o</STRONG>   While  <STRONG>tgoto</STRONG> is assumed to be used for the two-parameter cursor po-
           sitioning capability, termcap applications also use it for  single-
           parameter capabilities.

           Doing this shows a quirk in <STRONG>tgoto</STRONG>: most hardware terminals use cur-
           sor addressing with <EM>row</EM> first, but the original developers  of  the
           termcap  interface  chose  to  put the <EM>column</EM> parameter first.  The
           <STRONG>tgoto</STRONG> function swaps the order of parameters.  It  does  this  also
           for  calls  requiring  only  a single parameter.  In that case, the
           first parameter is merely a placeholder.

       <STRONG>o</STRONG>   Normally the ncurses library is compiled with terminfo support.  In
           that case, <STRONG>tgoto</STRONG> uses <STRONG><A HREF="curs_terminfo.3x.html">tparm(3x)</A></STRONG> (a more capable formatter).

           However,  <STRONG>tparm</STRONG>  is not a <EM>termcap</EM> feature, and portable <EM>termcap</EM> ap-
           plications should not rely upon its availability.

       The <STRONG>tputs</STRONG> routine is described on the  <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG>  manual  page.
       It can retrieve capabilities by either termcap or terminfo name.


</PRE><H3><a name="h3-Global-Variables">Global Variables</a></H3><PRE>
       The  variables <STRONG>PC</STRONG>, <STRONG>UP</STRONG> and <STRONG>BC</STRONG> are set by <STRONG>tgetent</STRONG> to the terminfo entry's
       data for <STRONG>pad_char</STRONG>, <STRONG>cursor_up</STRONG> and <STRONG>backspace_if_not_bs</STRONG>, respectively.  <STRONG>UP</STRONG>
       is  not used by ncurses.  <STRONG>PC</STRONG> is used in the <STRONG>tdelay_output</STRONG> function.  <STRONG>BC</STRONG>
       is used in the <STRONG>tgoto</STRONG> emulation.  The variable <STRONG>ospeed</STRONG> is set by  ncurses
       in a system-specific coding to reflect the terminal speed.


</PRE><H3><a name="h3-Releasing-Memory">Releasing Memory</a></H3><PRE>
       The  termcap  functions  provide  no  means for freeing memory, because
       legacy termcap implementations used only the buffer areas  provided  by
       the  caller  via <STRONG>tgetent</STRONG> and <STRONG>tgetstr</STRONG>.  Those buffers are unused in ter-
       minfo.

       On the other hand, terminfo allocates memory.  It uses <STRONG>setupterm</STRONG> to re-
       trieve the data used by <STRONG>tgetent</STRONG> and the functions which return capabil-
       ity values such as <STRONG>tgetstr</STRONG>.  One could use

            <STRONG>del_curterm(cur_term);</STRONG>


       to free this memory, but  there  is  an  additional  complication  with
       ncurses.   It uses a fixed-size <EM>pool</EM> of storage locations, one per set-
       ting of the <STRONG>TERM</STRONG> variable when <STRONG>tgetent</STRONG> is called.  The  <STRONG>screen(1)</STRONG>  pro-
       gram relies upon this arrangement, to improve its performance.

       An  application  which  uses only the low-level termcap functions could
       free the memory using <STRONG>del_curterm</STRONG>, because the pool is freed using oth-
       er functions (see <STRONG><A HREF="curs_memleaks.3x.html">curs_memleaks(3x)</A></STRONG>).


</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
       Except  where  explicitly noted, routines that return an integer return
       <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> (SVr4 only specifies "an  integer  value  other
       than <STRONG>ERR</STRONG>") upon successful completion.

       Routines that return pointers return <STRONG>NULL</STRONG> on error.


</PRE><H2><a name="h2-BUGS">BUGS</a></H2><PRE>
       If  you  call <STRONG>tgetstr</STRONG> to fetch <STRONG>ca</STRONG> or any other parameterized string, be
       aware that it will be returned in terminfo notation, not the older  and
       not-quite-compatible termcap notation.  This will not cause problems if
       all you do with it is call <STRONG>tgoto</STRONG> or <STRONG>tparm</STRONG>, which both expand  terminfo-
       style  strings as terminfo.  (The <STRONG>tgoto</STRONG> function, if configured to sup-
       port termcap, will check if the  string  is  indeed  terminfo-style  by
       looking  for  "%p"  parameters or "$&lt;..&gt;" delays, and invoke a termcap-
       style parser if the string does not appear to be terminfo).

       Because terminfo conventions for representing padding in  string  capa-
       bilities differ from termcap's, users can be surprised:

       <STRONG>o</STRONG>   <STRONG>tputs("50")</STRONG> in a terminfo system will put out a literal "50" rather
           than busy-waiting for 50 milliseconds.

       <STRONG>o</STRONG>   However, if ncurses is configured to support termcap, it  may  also
           have been configured to support the BSD-style padding.

           In that case, <STRONG>tputs</STRONG> inspects strings passed to it, looking for dig-
           its at the beginning of the string.

           <STRONG>tputs("50")</STRONG> in a termcap system may wait for 50 milliseconds rather
           than put out a literal "50"

       Note  that termcap has nothing analogous to terminfo's <STRONG>sgr</STRONG> string.  One
       consequence of this is that termcap applications  assume  <STRONG>me</STRONG>  (terminfo
       <STRONG>sgr0</STRONG>)  does not reset the alternate character set.  This implementation
       checks for, and modifies the data shown to the termcap interface to ac-
       commodate termcap's limitation in this respect.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>

</PRE><H3><a name="h3-Standards">Standards</a></H3><PRE>
       These  functions  are  provided for supporting legacy applications, and
       should not be used in new programs:

       <STRONG>o</STRONG>   The XSI Curses standard, Issue 4 describes these functions.  Howev-
           er,  they  are  marked TO BE WITHDRAWN and may be removed in future
           versions.

       <STRONG>o</STRONG>   X/Open Curses, Issue 5 (December 2007) marked the termcap interface
           (along with <STRONG>vwprintw</STRONG> and <STRONG>vwscanw</STRONG>) as withdrawn.

       Neither  the  XSI Curses standard nor the SVr4 man pages documented the
       return values of <STRONG>tgetent</STRONG> correctly, though all three were in  fact  re-
       turned  ever  since SVr1.  In particular, an omission in the XSI Curses
       documentation has been misinterpreted to mean that <STRONG>tgetent</STRONG>  returns  <STRONG>OK</STRONG>
       or  <STRONG>ERR</STRONG>.  Because the purpose of these functions is to provide compati-
       bility with the <EM>termcap</EM> library, that is a defect in XCurses, Issue  4,
       Version 2 rather than in ncurses.


</PRE><H3><a name="h3-Compatibility-with-BSD-Termcap">Compatibility with BSD Termcap</a></H3><PRE>
       External variables are provided for support of certain termcap applica-
       tions.  However, termcap applications' use of those variables is poorly
       documented, e.g., not distinguishing between input and output.  In par-
       ticular, some applications are reported to declare  and/or  modify  <STRONG>os-</STRONG>
       <STRONG>peed</STRONG>.

       The  comment that only the first two characters of the <STRONG>id</STRONG> parameter are
       used escapes many application developers.  The original BSD 4.2 termcap
       library (and historical relics thereof) did not require a trailing null
       NUL on the parameter name passed  to  <STRONG>tgetstr</STRONG>,  <STRONG>tgetnum</STRONG>  and  <STRONG>tgetflag</STRONG>.
       Some  applications  assume  that the termcap interface does not require
       the trailing NUL for the parameter name.  Taking into account these is-
       sues:

       <STRONG>o</STRONG>   As  a  special  case,  <STRONG>tgetflag</STRONG>  matched against a single-character
           identifier provided that was at the end of  the  terminal  descrip-
           tion.  You should not rely upon this behavior in portable programs.
           This implementation disallows matches against single-character  ca-
           pability names.

       <STRONG>o</STRONG>   This  implementation  disallows  matches  by  the termcap interface
           against extended capability names which are longer than two charac-
           ters.

       The BSD termcap function <STRONG>tgetent</STRONG> returns the text of a termcap entry in
       the buffer passed as an argument.  This library  (like  other  terminfo
       implementations) does not store terminal descriptions as text.  It sets
       the buffer contents to a null-terminated string.


</PRE><H3><a name="h3-Other-Compatibility">Other Compatibility</a></H3><PRE>
       This library includes a termcap.h header, for compatibility with  other
       implementations.   But  the header is rarely used because the other im-
       plementations are not strictly compatible.

       The original BSD termcap (through 4.3BSD) had no header file which gave
       function prototypes, because that was a feature of ANSI C.  BSD termcap
       was written several years before C was  standardized.   However,  there
       were two different termcap.h header files in the BSD sources:

       <STRONG>o</STRONG>   One  was used internally by the <STRONG>jove</STRONG> editor in 2BSD through 4.4BSD.
           It defined global symbols for the termcap variables which it used.

       <STRONG>o</STRONG>   The other appeared in 4.4BSD Lite Release 2 (mid-1993) as  part  of
           <EM>libedit</EM> (also known as the <EM>editline</EM> library).  The CSRG source his-
           tory shows that this was added in  mid-1992.   The  <EM>libedit</EM>  header
           file  was used internally, as a convenience for compiling the <EM>edit-</EM>
           <EM>line</EM> library.  It declared function prototypes, but no global vari-
           ables.

       The  header  file from <EM>libedit</EM> was added to NetBSD's termcap library in
       mid-1994.

       Meanwhile, GNU termcap was under development, starting  in  1990.   The
       first  release  (termcap 1.0) in 1991 included a termcap.h header.  The
       second release (termcap 1.1) in September 1992 modified the  header  to
       use <STRONG>const</STRONG> for the function prototypes in the header where one would ex-
       pect the parameters to be read-only.  This was a difference versus  the
       original  BSD  termcap.   The prototype for <STRONG>tputs</STRONG> also differed, but in
       that instance, it was <EM>libedit</EM> which differed from BSD termcap.

       A copy of GNU termcap 1.3 was bundled with <EM>bash</EM> in mid-1993, to support
       the <STRONG>readline(3)</STRONG> library.

       A  termcap.h  file was provided in ncurses 1.8.1 (November 1993).  That
       reflected influence by <STRONG>emacs(1)</STRONG> (rather than <STRONG>jove(1)</STRONG>) and GNU termcap:

       <STRONG>o</STRONG>   it provided declarations for a few global symbols used by <STRONG>emacs</STRONG>

       <STRONG>o</STRONG>   it provided function prototypes (using <STRONG>const</STRONG>).

       <STRONG>o</STRONG>   a prototype for <STRONG>tparam</STRONG> (a GNU termcap feature) was provided.

       Later (in mid-1996) the <STRONG>tparam</STRONG> function was removed from ncurses.  As a
       result,  there are differences between any of the four implementations,
       which must be taken into account by programs which can  work  with  all
       termcap library interfaces.


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG>putc(3)</STRONG>, <STRONG><A HREF="term_variables.3x.html">term_variables(3x)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>.

       https://invisible-island.net/ncurses/tctest.html



                                                              <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-Initialization">Initialization</a></li>
<li><a href="#h3-Capability-Values">Capability Values</a></li>
<li><a href="#h3-Formatting-Capabilities">Formatting Capabilities</a></li>
<li><a href="#h3-Global-Variables">Global Variables</a></li>
<li><a href="#h3-Releasing-Memory">Releasing Memory</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-BUGS">BUGS</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a>
<ul>
<li><a href="#h3-Standards">Standards</a></li>
<li><a href="#h3-Compatibility-with-BSD-Termcap">Compatibility with BSD Termcap</a></li>
<li><a href="#h3-Other-Compatibility">Other Compatibility</a></li>
</ul>
</li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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